Iraqi Kurdish leader Masud Barzani announced on October 15 that the preparations for the operation to liberate Mosul have been completed and it is time for the battle to begin.

"The time has come to begin the liberation of Mosul," a post on Barzani's official Twitter account said.

Forces from Iraq’s autonomous Kurdish region are expected to play a major role in the U.S.-backed offensive to recapture Mosul, Iraq’s second-largest city, seized by the Islamic State militant group in June 2014.

While the launch of the operation is expected to be announced soon, it will only mark the start of a difficult and complex battle.

The fight is likely to set off another humanitarian crisis. The United Nations has warned that up to 1 million people may be displaced by the fighting as winter sets in.

Turkish President Recep Tayyip Erdogan said on October 15 that Turkey will talk to its coalition partners about the possibility of joining the offensive at the Syria crisis talks in the Swiss city of Lausanne.

Turkey is worried that the offensive could be led by Shi’ite militia and include Kurdish militants it opposes. Turkey and Iraq are also at odds over the presence of Turkish troops in the Basiqa camp near Mosul.